1. Field of the Invention
The present invention relates to a method and apparatus for removing metallic matter (e.g. metal shavings, metal parts, iron, iron oxide and like metallic material from a flow stream of circulating oil well fluid, such as completion fluid.
2. General Background of the Invention
Magnets have been used to remove metal from a flow stream of oil well drilling mud. Examples of commercially available magnets can be seen at the Stacey Oil Services, Ltd. website (www.staceyoil.com) and the Ceesan website (www.ceesan.net). Such magnets are also known in the industry as “ditch magnets”. Some patents have issued for ditch magnets. One such patent is U.S. Pat. No. 3,498,455. Other possibly relevant patents are listed chronologically in the following table.
TABLEPAT. NO.TITLEISSUE DATE2,792,115Selective Quantity MeteringMay 14, 1957Dispenser For Granular Material3,498,455Ditch MagnetMar. 03, 19703,713,499Method and Apparatus for TreatingJan. 30, 1973Drilling Mud3,966,590Magnetic Ore SeparatorJun. 29, 19764,030,558Wear Determination of DrillingJun. 21, 1977Bits4,319,989Magnetic SeparatorMar. 16, 19825,740,919Magnetic SeparatorApr. 21, 19985,944,195Method for Separation of SolidsAug. 31, 1999from Drilling Fluids by MagneticSeparation and Centrifugation6,354,386Apparatus for Retrieving MetalMar. 12, 2002Objects from a Wellbore2006/0016732High Gradient Magnetic SeparatorJan. 26, 20062007/0138103Magnetic Separation in FluidsJun. 21, 2007
Cuttings that have been retrieved from a magnet that was placed in an oil and gas well circulating fluid stream can provide information that is beneficial to oil and gas well operators. These collected cuttings may indicate casing wear during ordinary drilling operations, pipe wear, or any other factor which may be economically detrimental to the well or production.
Time is an important factor in oil and gas well drilling. The cost of drilling is rising. With drilling, rig rates as expensive as they are, a small part of time saved can equate to significant savings. Present oil and gas well drilling rates can be as high as $125,000 to $600,000 per day. Thus, any procedure or apparatus that shortens the time for handling the magnet and/or its debris can be a significant savings in money.